According to this post within the current thread, it suggests you check the changelog for 1.6 as other IOS are now supported (which specifically I couldn't tell ya; but since you ask, it's a point in the right direction).

Newb question:
Using this app, how do you uninstall a wad if it is no longer on the SD card? I mean you can't seem to select an already installed wad to uninstall if the original wad is not on the SD card.